This app is an Implementation of early natural language processing through the well-known program ELIZA. It is intended for both recreational and educational purposes, and provides some insight into early work in artificial intelligence.

ELIZA is an early example of primitive natural language processing. ELIZA operated by processing users’ responses to scripts, the most famous of which was DOCTOR, a simulation of a session with a psychotherapist. Using almost no information about human though or emotion, this program sometimes provided a startlingly human-like interaction. ELIZA was written at MIT by Joseph Weizenbaum between 1964 and 1966.

This application is an implementation of the psychotherapist simulation using several unique interactive features of smartphones – namely voice recognition and text to speech. There are three sessions provided: a silent session that uses text input and provides text output to the display, a talking session using text to speech output for the therapist and voice recognition for the patient (the user) – the display also provides a log of the dialog, and a demonstration session with a patient input script. The talking session requires an internet connection, either 3G/4G or WiFi, to accomplish the voice to text recognition. The demonstration session contains fourteen responses from the patient and then recycles these repeatedly. The first time through makes sense since they have been designed for the simulated responses of the therapist. Patient responses become more nonsensical the second time through because they are not responding directly to the therapist’s statements as they do the first time through. Each of the three session allows a log of the session to be preserved through email.

The algorithm uses a list of keyword and key-phrases to find a match in the patient’s response – a short list of only thirty-eight. When a match is found, a corresponding phrase replaces the phrase that was matched. To avoid the appearance of repetition, substitutions cycle through a short sequence of three or four phrases. This is then followed by a simple substitution of pairs of words such as “I” for “You”, “You” for “I”, “Were” for “Was”, and so forth. This is actually a very short list of only seven substitutions that apply in both directions.